Metal replacement with lightweight materials is a major focus of the airline industry to achieve fuel economy. Carbon fiber reinforced thermoplastic composites are attractive candidates for load bearing parts in the aircrafts as the carbon fiber can significantly improve the mechanical properties of the thermoplastic resin used in the composite. A high loading of the carbon fibers in the thermoplastics is necessary to meet the stiffness and strength requirements of the load bearing parts where aluminum or other metals are currently being used. However, the high loading of carbon fibers causes a significant increase in melt viscosity of the composites that creates processing difficulties.
Polyetherimides are amorphous thermoplastic resins that have found applications in thermoplastic composites used in the aircraft industries due to their high glass transition temperatures, high heat resistance, good mechanical properties, low warpage and inherent flame retardant properties. The melt flow rate of polyetherimide composites are significantly lower compared to semicrystalline thermoplastic resin composites, e.g. polyphenylene sulfide, polyetheretherketone and the like, which prevents their use in large size load bearing parts, e.g. in aircraft seat back frames. There remain certain applications wherein an increased melt flow rate of polyetherimide composites than is currently available would be desirable. Low molecular weight polyetherimides offer higher flow but at the expense of other properties, e.g. impact strength.
In addition to processing requirements, a thermoplastic resin used in aircraft industries must also pass specified flammability tests that include a vertical Bunsen burner test, a heat release test and a smoke test. Historically, the heat release test, which is also known as the OSU (Ohio State University) test, is the most difficult test to pass with the thermoplastics. Thus, the challenge in developing thermoplastic composites lies in the manipulation of the thermoplastic composites to achieve a combination of good mechanical properties (e.g. high strength, high impact) and high flow while maintaining the OSU heat release compliancy.
Accordingly, there is a need for high flow polyetherimide composites, devices thereof and methods thereof that comprise carbon fiber, wherein the polyetherimide composites have high strength, e.g. strength that is similar or greater than that of die-cast aluminum, high impact; and are compliant with the OSU 65/65 heat-release parameters. Such thermoplastic composites, devices comprising thermoplastic composites, and methods related thereto are described herein.